1. Field of the Invention
The present invention relates to a photoacoustic image-generating apparatus which generates a photoacoustic image based on a photoacoustic wave caused by light irradiation. Also, the present invention relates to a method of controlling a light source in the photoacoustic image-generating apparatus.
2. Description of the Related Art
As a kind of an image inspection method capable of noninvasively inspecting the internal state of a living body, an ultrasonic inspection method is known. In the ultrasonic inspection, an ultrasonic probe which can transmit and receive an ultrasonic wave is used. If an ultrasonic wave is transmitted from the ultrasonic probe to a subject (living body), the ultrasonic wave advances through the inside of the living body and is reflected on a tissue interface. A reflected ultrasonic wave is received using the ultrasonic probe, and a distance is calculated based on the time until the reflected ultrasonic wave is returned to the ultrasonic probe, whereby the stage of the inside can be imaged.
Photoacoustic imaging for imaging the inside of a living body using a photoacoustic effect is known. In general, in photoacoustic imaging, the inside of a living body is irradiated with a pulsed laser light, such as a pulsed laser. In the inside of the living body, a tissue of the living body absorbs energy of the pulsed laser light, and an ultrasonic wave (photoacoustic wave) is generated due to adiabatic expansion caused by the absorbed energy. The photoacoustic wave is detected using an ultrasonic probe or the like, and a photoacoustic image is constituted based on the detection signal, whereby the inside of the living body can be visualized based on the photoacoustic wave.
JP2009-31262A describes a combination of biological information imaging using photoacoustics and treatment using a puncture needle. In JP2009-31262A, a physician or the like observes a photoacoustic image to view a diseased part, such as a tumor, a region suspected of a diseased part, or the like. In order to inspect such a region more accurately, or in order to perform injection or the like in the diseased part, cells are gathered or injection in the diseased part is performed using a puncture needle such as an injection needle or a cytologic needle. In JP2009-31262A, puncturing can be performed while observing the diseased part using the photoacoustic image.